Grassy open spaces are good for the soul and are certainly better for runoff than pavement, but the time Americans spend preening the perfect lawn might actually do more harm to the environment than good. Watering, leaf-blowing and mowing can take its toll. On average, tending to our lawns actually produces more carbon dioxide than a lawn can soak in. While there are things you can do to reduce your lawn's carbon footprint, the best option might be to look at more natural, native landscaping options that require less work, less fertilizer and less water to maintain.